1. Field
This invention relates to the field of aircraft and more particularly the fuselage of transport aircraft.
More precisely, the invention addresses an aircraft fuselage whose forward section is suitable for reducing the portion of the fuselage necessary for the cockpit and for improving the aerodynamic behavior of the fuselage, and that can be adapted for the extreme forward portion of different types of aircraft.
2. Brief Description of Related Developments
In the domain of modern transport aircraft design, such as civilian passenger or freight transport aircraft, the forward section of the fuselage 1, as shown in FIG. 1, is usually obtained by the gradual tapering of the forward tip 2 of the fuselage in front of a generally cylindrical rear section 3.
The transverse cross sections perpendicular to the longitudinal axis 10 of the fuselage 1 are accordingly progressively reduced to a point 21 with zero cross section, corresponding to the front extremity of the fuselage or the nose of the aircraft.
In practice, the cross sections are defined to satisfy certain technical and design constraints.
In the first place, it is necessary to provide for a cockpit 22 in the forward section 2 of the fuselage, located in the upper part above a floorboard 11, whose dimensions are relatively incompressible because of the technical personnel, pilot, copilot, and navigator, who are stationed there during flight, because of the need to provide for transparent areas, windshield and side windows sufficient to assure visibility compatible with standards, and because of the precise arrangement of the flight instruments.
Secondly, the working structure must be interrupted in front at an area with width and height dimensions sufficient to permit the installation of a radar antenna, most often mobile in current systems, that is covered by a protective radome for aerodynamic reasons in the first place, and that also must not obstruct visibility from the cockpit.
Thirdly, a front landing gear 4 must be positioned in a lower section of the front fuselage, and it is stored in a retracted position inside the fuselage 1, more precisely in a landing gear compartment 41 isolating the pressurized volume of the fuselage from the external unpressurized space, with the landing gear compartment closed off by hatches that assure the aerodynamic continuity of the fuselage in the position with retracted landing gear.
The front landing gear is also positioned on the fuselage in an area as far to the front as possible, for reasons of loading the front wheel relative to the principal landing gear located in an area of the aircraft farther to the rear.
Finally, beneath the floorboard 11 of the cockpit 22 and of the cabin 12 for the passengers or for any load, if needed there are equipment compartments 13 in front of cargo compartments 15, the necessary volume of which in practice is adapted by making a compartment more or less long to accommodate installation of all of the necessary equipment, which is of two principal types: technical equipment to monitor the aircraft, to conduct the flight and the mission, and equipment for commercial application to manage the services for the cabin passengers: lighting, temperature control, audio and video systems, meals, toilets, etc . . .
In practice, respecting numerous constraints imposes compromises on the geometry of the front fuselage, on the development of its cross sections, and on the apportionment of the different interior spaces and volumes, which have the effect of limiting the aerodynamic performance of the fuselage 1, by a relatively low position of the radome relative to the axis of the fuselage and by an elongation of the space occupied by the cockpit and the equipment compartments, and of generating industrialization constraints for the manufacture of the aircraft.